The Neanderthal Legacy: How their genes affect modern humans’ traits, behaviour and health

Nur Syarafina Mohamad Radzi, 11 Oct 2017

This reconstruction of a Neanderthal female unveiled in 2008 was the first made using ancient DNA evidence. Photo credit: Joe McNally, National Geographic Creative

You may have seen them portrayed as prehistoric cavemen in popular culture – with their short, stocky stature and prominent facial features. But, don’t be surprised to know that there may very well be a small part of the “caveman” genes in your body.

Modern day research has found that although Neanderthals became extinct around 40,000 years ago, evidences of Neanderthal genes have been found in the genomes of modern humans in Europe, Asia and Oceania. More interestingly, analysis shows that these genes to a certain extent can affect our physical traits, behaviour and health.

Physical traits and behaviour

The associations between Neanderthal DNA and human appearance and behavioural traits were analysed by computational biologist, Michael Dannemann, and his colleagues at Max Planck Institute for Evolutionary Anthropology. In the study, published in the American Journal of Human Genetics, researchers found the association of genetic material from Neanderthals with traits such as skin tone, hair colour and sleeping patterns.

Furthermore, many of the traits are somehow related to sun exposure. The explanation is that since Neanderthals lived in Eurasia approximately 100,000 years prior to modern humans’ arrival, they could adjust better to a wider range of daylight and lower ultraviolet radiation levels.

A tendency for evening activities, loneliness or isolation, low mood and smoking are also among the traits that were positively influenced by Neanderthal variants. “Skin and hair colour, circadian rhythms and mood are all influenced by light exposure. We speculate that their identification in our analysis suggests that sun exposure may have shaped Neanderthal phenotypes and that gene flow into modern humans continues to contribute to variation in these traits today,” researchers wrote.

How Neanderthal genes affect modern human health

According to a new study published in the Science journal, approximately 1.8% to 2.6% of the total genetic makeup for people of Eurasian ancestry is contributed by Neanderthal genes. In addition, findings from the study also suggest that Neanderthal genome match segments in certain modern humans, which are closely associated with health conditions such as blood cholesterol levels, schizophrenia, eating disorders and rheumatoid arthritis.

However, Neanderthal contributions still have their benefits, for example, protective genes against “bad” cholesterol. “A common misconception is the things that come from Neanderthals are generally bad, but that’s not entirely true,” says Kay Prüfer from the Max Planck Institute for Evolutionary Anthropology, who led the study.

Impact on modern medicine and society

The remarkable health and scientific discoveries made regarding the Neanderthal genome is more than just about satisfying our curiosity about the genetic legacy of our ancestors. Not only do these findings challenge previous assumptions about the human genome, but more importantly, a deeper understanding of the complex gene expression in modern humans may hold crucial answers to the current health issues that the global community is facing today. MIMS

Multimedia

Neanderthals 101: Who were the Neanderthals? Do humans really share some of their DNA? Learn facts about Neanderthals, the traits and tools of Homo neanderthalensis, and how the species fits into our evolution story. Video credit: National Geographic

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